VR6 backfire (??) :-(

[Critical_Mass 10]

Hi all,

 

Had an issue today, when started for the first time of the day. Started the car, fired up ok. I set off and when i switched into 2nd there was a small backfire. Went down the road to the shop and car was fine. Got back in car after being in shop turned car over and there was a big misfire and car didnt start. I tried again and it started fine and drove home fine.

 

I had misfiring issues a few weeks ago where a couple of the HT leads where arching onto the coilpack, RAC came and sprayed some white grease like stuff in the end of the HT leads and its been fine ever since. The only thing thats changed is ive switched back to Optimax for the last week or so.

 

Can anyone help and tell me what would cause this random backfire and whether i should be prepared for something needing to be replace eg coil pack?

 

Cheers

[RW1 0]

Given your recent history, I would look at the ignition leads.

 

Also remember the ignition fires the correct cylinder plus it also fires its twin even though its on the exhaust cycle. I suspect a cylinder is not firing properly and its then being fired when the exhaust valve is open.

The coil pack fires in pairs all the time.

 

Plus check its not now blown off the ISV silencer (black canister next to the ISV).

 

.

[Critical_Mass 10]

Cheers RW1, ill check the ISV canister.

 

Do you think its coil pack more then HT leads or vice versa?

[RW1 0]

Check on the leads are each roughly 5 Kohm resistance plus connections of connectors to leads are OK. Coil pack, may be but sparying the RAC "stuff" suggests an insulation leakage around the lead ends.

 

C.P. substitution will be the only way unless something is visibly wrong when you inspect the C.P..

 

.

[Critical_Mass 10]

cheers fella